Q143410: DOC: Vertical Slider Control Sends WM_VSCROLL Message

Article: Q143410
Product(s): Microsoft C Compiler
Version(s): winnt:4.0,4.1,4.2,5.0
Operating System(s): 
Keyword(s): kbdocfix kbdocerr kbCmnCtrls kbMFC kbScrollBar KbUIDesign kbVC400bug kbVC410fix kbGrpDS
Last Modified: 06-MAY-2001

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
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SUMMARY
=======

The following paragraph from MFC Technical Note 60 is incomplete.

"Slider Notification Messages

  A slider control notifies its parent window of user actions by sending the
  parent WM_HSCROLL messages. You can override the parent's OnHScroll member
  function to handle these messages. This function will be passed a
  notification code, the position of the slider, and a pointer to the
  CSliderCtrl object. Note that the pointer is of type CScrollBar* even though
  it points to a CSliderCtrl object. You may need to typecast this pointer if
  you need to manipulate the slider control."

  This information is true only for a HORIZONTAL slider control (a trackbar with
  the TBS_HORZ style). For a VERTICAL slider control (a trackbar with the
  TBS_VERT style), the WM_VSCROLL will be sent instead of the WM_HSCROLL
  message. You should override the parent's OnVScroll() member function to
  handle these messages.

In Visual C++, versions 5.0 and later, the above text is part of the help topic
titled "Slider Control Notification Messages."

MORE INFORMATION
================

The correct documentation can be found from the Trackbar Notification Messages
in Win32 SDK of Visual C++ 4.x Books Online.

A vertical slider control is used in the FIRE sample program. However, in the
sample OnHScroll() was overridden instead of OnVScroll(). Therefore, the code in
OnHScroll() (intended for the vertical slider control) will not be executed when
running this sample. Microsoft has confirmed this to be a bug in the sample in
Visual C++ 4.0. To fix this problem with FIRE, replace the OnHScroll() handler
with an OnVScroll() handler. This problem was corrected in Visual C++ 4.1.

Additional query words: CsliderCtrl Trackbar FIRE

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Keywords          : kbdocfix kbdocerr kbCmnCtrls kbMFC kbScrollBar KbUIDesign kbVC400bug kbVC410fix kbGrpDSMFCATL 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:4.0,4.1,4.2,5.0
Solution Type     : kbfix

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